Bactericidal quaternary ammonium compositions



United States Patent Ofice 3 493,660 BA'CTERICIDAL QIiATERNARY AMMONIUM COMPOSITIONS Norman W. Gill, Minneapolis, Minn., assignor t Cargill, Incorporated, Wilmington, Del., a corporation of Delaware No Drawing. Filed May 15, 1967, Ser. No. 638,575

Int. Cl. A01n 9/02, 9/20 U.S. Cl. 424329 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to quaternary ammonium compositions and more particularly it relates to quaternary ammonium compositions which exhibit high bactericidal effectiveness in the presence of hard water, and to bactericides containing such compositions.

The efficacy of a bactericide may be measured against two types of bacteria, those referred to as gram positive organisms, e.g., S, aureaus, and those generally referred to as gram negative organisms, e.g., E. coli and S. typhosa. For many disinfecting uses a bactericide having high bactericidal effectiveness against gram negative organisms is desirable.

The bactericidal activity of quaternary ammonium compounds against both gram positive and gram negative organisms is generally known. Substantially all long chain alkyl quaternary ammonium compounds exhibit some bactericidal activity. Those quaternary ammonium bactericides conventionally employed as bactericides have good bactericidal properties when tested against gram positive bacteria by the standard phenol or AOAC use dilution tests. However, the effectiveness of quaternary ammonium bactericides against gram negative organisms, for example, E. coli and S. typhosa has not been as good as might be desired, particularly in the presence of hard water.

Quaternary ammonium compounds containing a single long chain alkyl radical having from 8 to 18 carbon atoms and a benzyl radical have generally been considered to have the best bactericidal effectiveness against gram negative organisms. Maximum bactericidal effectiveness of known quaternary ammonium bactericides is achieved when the monoalkyl radical is a mixture of dodecyl (C tetradecyl (C hexadecyl (C and octadecyl (C radicals. Alkyl radicals of lesser chain length have been found to have lower bactericidal effectiveness. The bactericidal effectiveness of dialkyl benzyl quaternary ammonium compounds is likewise substantially less than monoalkyl benzyl quaternary ammonium compounds.

Quaternary ammonium bactericides find many uses as 3,493,660 Patented Feb. 3, 1970 sanitizers, algicides, etc., where they are employed in aqueous systems at relatively low concentrations, e.g., to 1000 ppm. Accordingly, a bactericide should have good bactericidal effectiveness in the presence of hard water. The hard water tolerance of a bactericide may be measured by a standard hard water tolerance test, known as the Chambers test. The Chambers test is a modification of the Weber-Black test (Journal of the American l-ublic Health Association, 38, 1405 [1948]).

In the Chambers hard water tolerance test a hundred milliliter test solution is prepared consisting of one milliliter of a bacterial inoculum, one milliliter of an aqueous solution of the bactericide to be tested, with the remainder being synthetic hard water. The concerntration of bacteria in the inoculum is controlled so that the test solution contains between about 75 million and million bacteria per milliliter.

The percentage of bacteria killed after certain specified intervals of time is measured to determine the tolerance of the bactericide to hard water.

Known long chain monoalkyl diamethyl benzyl quaternary ammonium bactericides generally have Chambers hard water tolerances between about 200 and about 750. Some specific types of quaternary compounds have higher Chambers values, but these compounds are generally more complex and are more difficult to manufacture. Known quaternary ammonium compounds which do not contain benzyl radicals generally have lesser Chambers hard water tolerances and are not generally considered to be effective bactericides.

It is a principal object of the invention to provide an easily prepared quaternary ammonium bactericide which exhibits high bactericidal effectiveness against gram negative organisms, particularly when in the presence of hard Water. Another object is to provide a quaternary ammonium compound which has good water solubility. A further object is to provide a mixture of quaternary ammonium compounds having ahigh Chambers hard water tolerance which do not contain benzyl radicals.

Very generally, the present invention is directed to a quaternary ammonium composition which exhibits improved bactericidal effectiveness, particularly against gram negative organisms in the presence of hard water, and which had good solubility in Water. More particularly, the invention is directed to a quaternary ammonium bactericide which includes as its principal bactericidal agent a di-(alkoxypropyl)-quaternary ammonium compound or a mixture of di-(alkoxypropyl)-guaternary ammonium compounds having alkoxypropyl radicals which contain alkyl groups having different chain lengths. The alkoxypropyl radicals containing alkyl groups of different chain length may be in the same molecule or in different molecules.

In certain specific instances the bactericide of the invention may contain only di-(alkoxypropyl)-quaternary compounds which have alkoxypropyl radicals containing alkyl groups of the same chain length. In such instances, the Chambers hard water tolerance is less than that obtained when the quaternary ammonium compounds contain alkoxypropyl radicals having alkyl groups of different chain length. However, the hard water tolerance of the bactericide is comparable to that obtained with known monolkyl dimethyl benzyl quaternary ammonium compounds.

The quaternary ammonium compounds of the present invention have the formula:

RocHtcmoI-n R3 RoomcHtCr-n R4 in which R is a straight or branched chain, saturated or unsaturated alkyl radical of from 8 to carbon atoms, R is a saturated alkyl of 1 to 3 carbon atoms, R, is a saturated alkyl radical of l to 3 carbon atoms or a benzyl radical and X is a salt forming anion. R and R are preferably methyl radicals. The salt forming anion may be a halogen, alkyl sulfate of from 1 to 4 carbon atoms, citrate, tartrate, sulfamate, nitrate, hydroxide, or any other anionic compound which is soluble in water at intended use levels and does not deleteriously affect the bactericide. In most instances a chloride or methyl sulfate anion is employed.

It has been discovered that a particular group of di- (alkoxypropyl)-quaternary ammonium compounds exhibit surprisingly improved bactericidal effectiveness against gram negative organisms in the presence of hard water. Heretofore, high bactericidal activity against gram negative organisms in hard water could be obtained only with monoalkyl dimethyl benzyl quaternary ammonium compounds. Surprisingly, the quaternary ammonium bactericide of the present invention exhibits high bactericidal effectiveness against gram negative organisms in the presence of hard Water regardless of whether the quaternary ammonium compounds contain benzyl groups. In preferred forms of the invention superior hard water tolerances against gram negative organisms are obtained when the quaternary ammonium compounds do not contain benzyl radicals.

It has also been determined that the quaternary ammonium compounds which form the bactericide of the invention should contain two alkoxypropyl radicals in order to provide the desired bactericidal effectiveness against gram negative organisms in hard water systems. Monoalkoxypropyl quaternary ammonium compounds and mixtures of these compounds do not achieve the high bactericidal effectiveness of di-(alkoxypropyl)-quaternary ammonium compounds. Further, the bactericidal effectiveness and solubility of the quaternary ammonium compounds is enhanced by the presence of an ether linkage in the alkyl containing radicals. Similar compounds containing dialkyl radicals, but without an ether linkage, have substantially reduced bactericidal effectiveness against gram negative organisms in the presence of hard water.

Superior bacterial etfectiveness against gram negative organisms is obtained when the bactericides contain di-(alkoxypropyl)-quaternary ammonium compounds containing alkyl groups of different chain lengths and do not contain benzyl radicals. Further, it has been determined that best results are obtained when the di-(alkoxypropyl)- quaternary ammonium compound contains alkyl groups of different chain lengths in the same molecule.

Alkyl groups of different chain lengths are obtained in the same molecule when the quaternary ammonium compound is prepared from alkyl alcohol raw materials which are a mixture of different chain length alcohols. For example, if the alcohol raw material is a 60 percent-40 percent mixture of n-octyl (C and n-decyl (C alcohols, the quaternary ammonium compound formed from the mixed alcohol raw materials will contain some molecules having two octyloxypropyl radicals, some molecules having two decyloxypropyl radicals, and some molecules having one octyloxypropyl radical and one decyloxypropyl radical.

The di-(alkoxypropyl)-quaternary ammonium compounds which form the bactericide may be prepared in accordance with standard techniques. One example of such a process includes reacting an alkyl alcohol which may contain mixed alkyl chains with acrylonitrile followed by subsequent hydrogenation of the resulting ether nitrile and finally quaternizing with an alkyl halide or dialkyl sulfate. More specifically, a preferred preparation consists of charging to a reaction vessel an amount of an alkyl alcohol or mixed alkyl alcohols equivalent to about nine moles of the alcohol and about 0.1 percent potassium hydroxide based on the weight of the alcohol. About 20 mole percent excess of acrylonitrile, based on the alcohol or mixture of alcohols, is added slowly to the reaction vessel while the reaction mixture is maintained from 25- 35 C. The reaction is completed within 5 to 7 hours. The mixture is then neutralized with glacial acetic acid equal to 1.1 times the chemical equivalent of the quanity of potassium hydroxide, solid residue is removed by then filtering, and excess acrylonitrile is vacuum distilled off, leaving an alkoxypropyl nitrile product.

An amount of the alkoxypropyl nitrile product equivalent to between 3.5 and 4.0 moles is then charged to a reaction vessel, equipped to withstand pressures of 1000 p.s.i.g., along with about 10 g. of Raney nickel. The reactor is then pressurized to about 25 p.s.i.g. with hydrogen and heated to between 300 F and 350 F. When the hydrogenation reaction is initiated the temperature is held at about 400 F. and the hydrogen pressure increased to 150 p.s.i.g. The hydrogen is continually circulated and washed to remove any undesirable gases, such as ammonia, during the course of the reaction. The duration of the hydrogenation reaction is between 1 and 3 hours after which the catalyst is removed leaving a di-(alkoxypropyl)-amine product.

An amount of di-(alkoxypropyl) amine equivalent to about 0.5 mole is then charged to a reaction vessel equipped to withstand pressure up to 500 p.s.i.g. along with 190 grams of isopropanol, 10 grams of water and about 1.25 moles of sodium bicarbonate. The reaction vessel is sparged with nitrogen to remove air, and methyl chloride is added until the pressure inside the vessel reaches 50-70 p.s.i.g. The vessel is then heated to a temperature between 70 C. and C. The reaction mixture is agitated slightly and the reaction is completed in 3 to 5 hours. Periodic venting of the reaction mixture to remove carbon dioxide is advantageous, followed by addition of methyl chloride until a pressure of between 50 to 70 p.s.i.g. is obtained. The reaction is considered complete when the free amine value is between 1.50.5. Solid residue is removed by filtering. The soluble reaction mixture remaining consists essentially of di-(alkoxypropyl) dimethyl ammonium chlorides.

It is apparent that other processes and modifications are possible to prepare the di-(alkoxypropyl)-quaternary ammonium compounds which form the bactericide of the invention, and applicant does not intend to be limited to the described method.

The surprisingly good bactericidal effectiveness of a bactericide of the invention can be demonstrated by the Chambers hard water tolerance test. In the Chambers hard water tolerance test described herein, milliliters of test solution was employed. The test solution consisted of 1 milliliter of an inoculum containing E. Coli USPHS No. 198, Strain ATCC No. 11229, containing sulficient bacteria to provide between about 75 million and million bacteria per milliliter of test solution at the start of the test, one milliliter of the bactericide to be tested in an amount to give 200 parts per million of bactericide in the test solution. The remainder of the test solution was a synthetic hard water having a controlled hardness equivalent to a stated number of parts per million, calculated as calcium carbonate. In each instance herein which a hard water tolerance is set forth, the kill of E. coli is at least 99.999 percent within 30 seconds, based upon a concentration of bactericide of 200 parts per million of active ingredients.

Using a Chamber hard water tolerance test as set forth above, the following results were obtained in testing monoalkyl dimethyl benzyl quaternary ammonium bactericides available in commerce, dialkyl dimethyl quaternary ammonium compounds, and monoalkoxypropyl trimethyl quaternary ammonium compounds.

1 1:1 mixture of 5% C12, 60% C14, 30% Cu, 5% Cm, and 50% C12, 30% C 17% Cm, 3% C13 n-alkyl dimethyl ammonium chlorides.

140?, C12, 50% C14, 10% Cm n-alkyl dimethyl benzyl ammonium e 1 OH es.

3 60/40 mixture of C8, C10 n-dialkyl dimethyl ammonium chlorides. 1 1 60510 mixture of C3, C1 n-alkoxypropyl trimethyl ammonium c 1 OH es.

TABLE II Chambers hard water Example Composition tolerance 5 [(CeHiaO (CH2ls)2N(CHa)2] Cl' 50 [(CaHnO(OI'Iz)a)2N(CHa)2]+Cl-. 450 [(CioH210 (CHmhN (CH T011. 400 8 [(C12H25O (CH2):i)2N(CH3)2 +C1- 100 It will be seen that di-(alkoxypropyl) dimethyl ammonium chlorides containing 8 or 10 carbon atoms in the alkyl group show a much improved Chambers hard water tolerance as compared to similar compounds containing 6 or 12 carbon atoms in the alkyl group. Further, these compounds have about as good hard water tolerance as do the monoalkyl dimethyl benzyl compounds of Table l, and are considered to be eifective bactericidal agents for use in water systems.

In accordance with the preferred form of the invention, the di-(alkoxypropyl)-quaternary ammonium compounds are prepared from a mixture of alkyl alcohols of different chain lengths in order that the quaternary ammonium product will comprise a mixture of different compounds containing, for example, molecules having two C alkyl groups, molecules having two C alkyl groups, and molecules having one C alkyl group, and one C alkyl group. When mixed alkyl alcohol raw materials are employed, it has been determined that at least about 30 percent, and usually about 45 percent, of the di- (alkoxypropyl)-quaternary ammonium product will be of the type which has alkoxypropyl radicals having alkyl groups of different chain lengths on the same molecule.

Surprisingly improved Chambers hard water tolerances are obtained when these quaternary ammonium products are employed as bactericides. Table III illustrates results obtained when mixtures of n-alkyl alcohols were employed as raw materials to prepare mixtures of di-(alkoxypropyl)-dimethyl ammonium chlorides. In each example a 60/40 weight percent mixture of alcohol was used:

TABLE III Chambers hard Example Alcohol raw material water tolerance 9- 60% C6 40%CB 50 10.. 60% Ctr-40% 010-. 11. 60% 05-40% C1 200 12-- 60% Cir-40% C10 900 13. 60% Cs40% C12 600 14. 60% Clo-40% C12. 400 15 C12C151 300 1 Cut of petroleum alcohols, which also contains C13 and Cu alcohols, having approximately a 3:2 ratio of C12: C15- Examination of Table III clearly indicates that unexpected bactericidal efiectiveness is obtained when the alkyl groups of the alkoxypropyl radicals contain from 8 to 15 carbon atoms. Further, a substantial improvement in bactericidal eifectiveness is obtained when using a mixture of n-alkyl C -C and C -C alcohol raw materials as compared to similar compounds (Table II) in which the alcohol raw material was a n-alkyl alcohol of a single chain length.

To determine optimum ratios of the alcohol raw materials C -C di-(alkoxypropyl)-dimethyl ammonium chlorides were prepared from different ratios of alcohols. The results are set forth in Table IV.

TABLE IV Chambers hard Example Table IV clearly illustrates that an alcohol raw material mixture of between about 20 percent and about percent by weight n-octyl alcohol, and between about 80 percent and about 20 percent n-decyl alcohol results in a di-(alkoxypropyl)-quaternary ammonium product of improved bactericidal etfectiveness. Best results are obtained when the alcohol raw material is a mixture of about 60 percent n-octyl alcohol and about 40 percent n-decyl.

In addition to the improved bactericidal effectiveness obtained when the quaternary ammonium compounds are prepared from mixed alcohol raw materials, it has also been determined that improved bactericidal eliectiveness is obtained when di-(alkoxypropyl)-quaternary ammonium compounds prepared from single alcohol raw materials (i.e., when both alkoxypropyl radicals of the molecule have alkyl groups of the same chain length) are mixed together after preparation. Table V illustrates results obtained utilizing various physical mixtures of di-(octyloxypropyl)-dimethyl ammonium chloride and di-(decyloxypropyl)-dimethyl ammonium chloride.

TABLE V Ratio of dioctyl to didecyl ammonium chloride 22 di C Chambers hard water tolerance Example 80% (ll 03-20% dl Cup... 750 60% (ii C3407; dl (1 0.... 750 25 40% (ll (la-60% A1 (110.... 750 26 20% (lips-80% dl C10... 600 27. 100% (ll C10 400 and that this improvement is significant when the mixture of compounds contains between about 80% and about 20% of one quaternary ammonium, compound, and between about 20% and about 80% of the other quaternary ammonium compound.

Di-(alkoxypropyl)-quaternary ammonium compounds in which one methyl radical is replaced by a benzyl radical also exhibit bactericidal effectiveness, although somewhat lesser than similar compounds which do not contain a benzyl radical. A C C di-(alkoxypropyD- methyl benzyl quaternary ammonium compound, prepared from a 60/40 mixture of n-octyl and n-decyl alcohol raw materials has a Chambers hard Water tolerance of about 500. This is comparable to the Chambers hard water tolerance of conventional monoalkyl dimethyl benzyl quaternary ammonium compounds of the type described in Table I, and di-(alkoxypropyl)-methyl benzyl quaternary ammonium compounds are considered to be useful bactericides. However, their bactericidal effectiveness is not as good as similar compounds which do not contain benzyl radicals (Table III).

Bactericides containing the described quaternary ammonium compounds as their principal active agent are useful as sanitizers, algicides and as additives to feed water for poultry. The bactericides may be used by themselves or in admixture with various nonionic detergents and builders. A bactericide incorporating the compositions of the invention may be prepared by preparing a mixture of 50 percent by weight of the di-(a1koxypropyl)- quaternary ammonium compound, percent by weight isopropanol, or other lower alkyl alcohol, and 35 percent by weight of water. Of course other formulations are also contemplated.

It can be seen that a novel quaternary ammonium composition has been described. The quaternary ammonium composition has unusually high bactericidal effectiveness in the presence of hard Water. Although certain features of the invention have been set forth with particularity in order to accurately describe the invention, alternative embodiments within the skill of the art are contemplated.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. A quaternary ammonium bactericide of high bactericide of high bactericidal effectiveness which includes as its principal bactericidal agent a mixture comprising a compound of the formula R1OCH2CH2CH2 Rs R1OCHZCH2CH2 R4 and a compound of the' formula R30 CHZCH2OHZ R3+ V R20 CHZOIIZCHQ R4 Where R and R are straight or branched chain, saturated or unsaturated alkyl of from 8 to 15 carbon atoms, R is saturated alkyl of 1 to 3 carbon atoms, R is saturated alkyl of 1 to 3 carbon atoms or benzyl, X is a water soluble salt forming anion, and R and R are different, and whereby the bactericidal effectiveness of the mixture as tested in hard water is greater than the effectivenessof either component of the mixture alone.

2. A quaternary ammonium bactericide in accordance with claim 1 which in addition includes a compound of the formula RzOCIhCHzCfiz \R4 where R and R are straight or branched chain, saturated or unsaturated alkyl of from 8 to 15 carbon atoms, R is saturated alkyl of 1 to 3 carbon atoms, R; is saturated alkyl of 1 to 3 carbon atoms or benzyl, X is a water soluble salt forming anion, and R and R are different.

3. A quaternary ammonium bactericide in accordance with claim 2 wherein R and R are methyl and X is chloride.

4. A quaternary ammonium bactericide in accordance With claim 3 Where R is n-octyl and R is n-decyl.

References Cited UNITED STATES PATENTS 2,692,286 10/1954 Stayner 260567.6 2,746,928 5/1956 Darragh et a1. 260567.6

FRANK CACCIAPAGLIA, JR., Primary Examiner V. D. TURNER, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,493,660 Dated February 3, 1970 Inventor( Norman W. Gill It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 14 "concentration" is misspelled.

Column 2, line 44, change "had" to has-.

Column 2, line 48, "quaternary" is misspelled.

Column 2, line 64, change "monolkyl" to --monoalkyl--.

Column 4, line 33, change "pressure" to -pressures--.

Column 4, line 68, after "herein" insert --in-.

Column 7, line 46, delete "of high bactericide" SIGNED AND SEALED AUG-251970 (SEAL) Attost:

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